Devices for sensing a degree of rotation for angular disposition are critically important in remotely located mechanisms where a visual monitoring cannot be made. The need for accurate angular measuring devices particularly is felt in the broadening and the highly sophisticated field of robotics where precision unattended and unmonitored mechanical functions are to be flawlessly coordinated.
Hand-like manipulators having a number of interdependent articulated sections pose a still more formidable problem since most conventional potentiometer angular sensors are bulky and are susceptible to damage. The potentiometer sensors have shown a somewhat acceptable degree of resolution by providing indications of changed resistance, or voltage, but they are vulnerable to failure particularly when the manipulator or articulated joint is to be used in marine applications, most notably high pressure applications. When a number of potentiometer angular sensors are located in a small volume (on all the joints of a hand-like manipulator), an objectionable bulk is created. In addition, the group of potentiometer sensors cannot be operated without special precautions for underwater or adverse environments that can effect its resistance or the supplied electricity.
Thus, there is a continuing need in the state-of-the-art for an angular position indicator that is compact and reliable under adverse conditions to allow its use in an undersea manipulator or articulated joint to provide accurate angular position readings.